%0 Journal Article %1 Behr2006 %A Behr, B. %A Hoffmann, C. %A Ottolina, G. %A Klotz, K. N. %D 2006 %J J Biol Chem %K Acid Acid/genetics Adrenergic Amino Animals Aspartic Assay CHO Cricetinae Data Humans Isoleucine/genetics Isoxazoles/metabolism/pharmacology Ligands Lysine/genetics Molecular Mutagenesis Protein Radioligand Secondary Sequence Structure, Terbutaline/metabolism/pharmacology Tertiary Valine/genetics beta-1/chemistry/*genetics/*metabolism beta-Agonists/metabolism/pharmacology Receptor Cell %N 26 %P 18120-5 %T Novel mutants of the human beta1-adrenergic receptor reveal amino acids relevant for receptor activation %U http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16648137 %V 281 %X Activation of G protein-coupled receptors like the beta(1)-adrenergic receptor results in conformational changes that ultimately lead to signal propagation through a G protein to an effector like adenylyl cyclase. In this study we identified amino acids that seem to be critical for activation of the human beta(1)-adrenergic receptor. Activation patterns of mutant receptors were analyzed using two structurally different ligands for beta-adrenergic receptors that both are mixed agonist/antagonists. Broxaterol and terbutaline are agonists at beta(2)- and beta(3)-receptors; however, they act as antagonists at the beta(1)-subtype. We reasoned that this functional selectivity may be reflected by a corresponding sequence pattern in the receptor subtypes. Therefore, we exchanged single amino acids of the beta(1)-adrenergic receptor for residues that were identical in the beta(2)- and beta(3)-subtypes but different in the beta(1)-receptor. Pharmacological characterization of such receptor mutants revealed that binding of a panel of agonists and antagonists including broxaterol and terbutaline was unaltered. However, two of the mutants (I185V and D212N) were activated by broxaterol and terbutaline, which acted as antagonists at the wild-type receptor. Two additional mutants (V120L and K253R) could be activated by terbutaline alone, which is structurally more closely related to endogenous catecholamines like epinephrine than to broxaterol. A model of the human beta(1)-adrenergic receptor showed that the four gain-of-function mutations are outside of the putative ligand-binding domain substantiating the lack of an effect of the mutations on binding characteristics. These results support the notion that Val-120, Ile-185, Asp-212, and Lys-253 are critically involved in conformational changes occurring during receptor activation.

@article{Behr2006, abstract = {Activation of G protein-coupled receptors like the beta(1)-adrenergic receptor results in conformational changes that ultimately lead to signal propagation through a G protein to an effector like adenylyl cyclase. In this study we identified amino acids that seem to be critical for activation of the human beta(1)-adrenergic receptor. Activation patterns of mutant receptors were analyzed using two structurally different ligands for beta-adrenergic receptors that both are mixed agonist/antagonists. Broxaterol and terbutaline are agonists at beta(2)- and beta(3)-receptors; however, they act as antagonists at the beta(1)-subtype. We reasoned that this functional selectivity may be reflected by a corresponding sequence pattern in the receptor subtypes. Therefore, we exchanged single amino acids of the beta(1)-adrenergic receptor for residues that were identical in the beta(2)- and beta(3)-subtypes but different in the beta(1)-receptor. Pharmacological characterization of such receptor mutants revealed that binding of a panel of agonists and antagonists including broxaterol and terbutaline was unaltered. However, two of the mutants (I185V and D212N) were activated by broxaterol and terbutaline, which acted as antagonists at the wild-type receptor. Two additional mutants (V120L and K253R) could be activated by terbutaline alone, which is structurally more closely related to endogenous catecholamines like epinephrine than to broxaterol. A model of the human beta(1)-adrenergic receptor showed that the four gain-of-function mutations are outside of the putative ligand-binding domain substantiating the lack of an effect of the mutations on binding characteristics. These results support the notion that Val-120, Ile-185, Asp-212, and Lys-253 are critically involved in conformational changes occurring during receptor activation.}, added-at = {2010-12-14T18:12:02.000+0100}, author = {Behr, B. and Hoffmann, C. and Ottolina, G. and Klotz, K. N.}, biburl = {https://www.bibsonomy.org/bibtex/216976f72d230a16c85f50b04204411eb/pharmawuerz}, endnotereftype = {Journal Article}, interhash = {f2f866769ceea27db0133d3e0fd24951}, intrahash = {16976f72d230a16c85f50b04204411eb}, issn = {0021-9258 (Print) 0021-9258 (Linking)}, journal = {J Biol Chem}, keywords = {Acid Acid/genetics Adrenergic Amino Animals Aspartic Assay CHO Cricetinae Data Humans Isoleucine/genetics Isoxazoles/metabolism/pharmacology Ligands Lysine/genetics Molecular Mutagenesis Protein Radioligand Secondary Sequence Structure, Terbutaline/metabolism/pharmacology Tertiary Valine/genetics beta-1/chemistry/*genetics/*metabolism beta-Agonists/metabolism/pharmacology Receptor Cell}, month = {Jun 30}, note = {Behr, Bjorn Hoffmann, Carsten Ottolina, Gianluca Klotz, Karl-Norbert Research Support, Non-U.S. Gov't United States The Journal of biological chemistry J Biol Chem. 2006 Jun 30;281(26):18120-5. Epub 2006 Apr 28.}, number = 26, pages = {18120-5}, shorttitle = {Novel mutants of the human beta1-adrenergic receptor reveal amino acids relevant for receptor activation}, timestamp = {2010-12-14T18:22:38.000+0100}, title = {Novel mutants of the human beta1-adrenergic receptor reveal amino acids relevant for receptor activation}, url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16648137}, volume = 281, year = 2006 }